Picture this: You look through a peephole and stare straight ahead. You see everything above, below, and to your sides.
Suddenly, the peephole gets smaller and smaller. You see everything in front of you, but everything above, below, and around you goes black. It’s like you’re looking through a narrow tube or a tunnel. This is how it feels to have “tunnel vision” – a loss of your peripheral vision. What is peripheral vision? It’s what allows you to see objects all around you without turning your head or moving your eyes. It helps you to sense motion and walk without crashing into things. It’s what you use to see something “out of the corner of your eye.” Most often, it’s a side effect of other medical conditions. Two of these, glaucoma and retinitis pigmentosa, are among the most common. Glaucoma: This disease is caused by the buildup of fluid and pressure in the eye. It can damage the nerve that carries information from the eye to the brain. When this happens, you may lose your peripheral vision. Over time, you could lose all of your eyesight. Luckily, doctors can prevent vision loss if they find your glaucoma early. Retinitis Pigmentosa (RP): This genetic disorder damages the retina, the part of the eye that senses light. Night blindness is one of the first symptoms. You might also have a hard time telling different colors apart. Over time, you’ll notice changes in your peripheral vision. You can get this condition at any age, but it usually strikes teens and young adults. Most people who have it are legally blind by age 40.